The present invention relates to an open ended, cup-shaped container made from plastic material and adapted for use as a cream, yogurt, milk or similar liquid container. Particularly, the present invention relates to a plastic container made for example by injection molding, provided with a unitary conical or cylindrical body closed at its bottom and having a variable thickness in selected areas of its wall. The body may be also provided with a circumferential flange lip about its open end to which a cover or foil may be attached.
In the mass production of plastic cups such as those described above, it is most desireable to maintain the material usage as small as possible. For this reason, efforts are made to mold the walls of the cup from thin material and provide the same with sufficient stiffness by the use of corresponding corrugated profiles so that the wall thickness compared with smooth wall cups can be reduced, while the strength retained.
Cups are known in this art by which the peripheral wall is formed with alternate and substantially parallel inner and outer longitudinal ribs and lengthwise indentations in either horizontal or vertical orientation. These ribs form a corrugated or undulating surface, the crests, backbone or crown of the ribs serving as gripping surfaces by which the cup may be picked up or handled. Because of the manipulation of the body walls in the formation of the ribs, a very thin material cannot be used for the basic structure. It has, therefore, become known, to form the crown or crest of the ribs, on at least one side of the container wall, with a reinforcement, as for example, an increase in material thickness, or by the insertion of an additional member to make it stronger. Cups made with profiled peripheral walls and reinforced ribs, permit some saving in material particularly over those earlier cups having smooth thicker walls. However, because the corrugations subject the wall surface to distention and enlargement, if viewed in a planar development, and because material spills or flows over into adjacent portions of the remaining peripheral wall areas, the actual savings in material is virtually insignificant.
It is an object of the present invention to provide a complete plastic cup-like container having substantial material savings over the prior products without any reduction in strength.
Further objects and disadvantages will be seen from the following disclosure of the present invention.